
Introduction
"Sage is a free opensource mathematics software system licensed under the GPL. It combines the power of many existing opensource packages into a common Pythonbased interface."
"Mission: Creating a viable free open source alternative to Magma, Maple, Mathematica and Matlab."
Website: http://www.sagemath.org/
Installation Instructions
For most recent versions of Ubuntu, you can install with a PPA using the following commands in a terminal:
aptaddrepository y ppa:aims/sagemath aptget update aptget install sagemathupstreambinary
Download binaries from their website
Go to the website
and pick up a mirror to download. Choose 'Download for Linux', then
 choose your architecture (32 or 64 bit),
 then choose the 'lzma' package with the word Ubuntu and your Ubuntu version in the name.
if you use the Metalinks mirror then see http://wiki.sagemath.org/DownloadAndInstallationGuide#Metalink for help
For example, for a 32bit processor running Ubuntu 10.4, you'd select sage4.4.4linux32bitubuntu_10.04_ltsi686Linux.tar.lzma where 4.4.4 is the latest Sage version at the time of writing.
Installing reduces to unpacking into /opt (or any other location of your choice), and putting a link to the sage executable in /usr/local/bin:
sudo su cd /opt tar lzma xvf /path_to_sage_package/sage?.?.?linuxubuntu...lzma ln s /opt/sage.???.../sage /usr/local/bin/sage sage
Compile from source
You can compile sage from source. Though it's actually very easy, it may take a long time (1 hour on high end hardware, 14 days on a cell phone).
The first step is to install the required packages:
sudo aptget upgrade && sudo aptget install buildessential m4 gfortran
And you may also need the following for some extra features
sudo aptget install imagemagick texlive dvipng
Then you can compile the code with:
make
You can now use sage from that directory or move it into /opt:
sudo su cd /opt cp r /path_to_sage . ln s /opt/sage.???.../sage /usr/local/bin/sage
You should check their own documentation if you find any trouble: http://sagemath.org/downloadsource.html
Create an icon in the panel
You can add to the panel an icon for starting the sage server. Just select "add new element to the panel", "add new applet" or however it's called in your system, then choose for a new "Launcher" or "Launcher for external applications".
In the configuration dialog for the launcher, make sure you select "open in a terminal" and choose "sage notebook" for the command in GNOME or XFCE. In KDE, choose "sage" for the command and "notebook" for command line options.
You can use "SAGE" for the name and the following for the icon:
/opt/sagedirectory.../data/extcode/notebook/images/icon48x48.png
where "sagedirectory..." is the directory where you installed sage.
Getting Started With Sage
Open a terminal and type sage and press enter. The sage command line interface should start up. Wait for the sage prompt to come up. It would looks thus:
sage:
This may take up to a minute depending on your hardware.
The first time you use Sage you will be asked to set a password to secure your work.
Choice of Sage Interface: Command Line Or GUI
You have a choice of using Sage either from the command line or from a GUI. The official GUI is called the notebook. In order to use the notebook interface to sage use the sage prompt to type:
notebook()
This will open the Firefox web browser showing the notebook.
To start work with the notebook click on the link New Worksheet.
The rest involves typing your sage commands into the input box and clicking the evaluate button that lies below it.
You might also use the program Cantor or TeXmacs as an interface, though they're not as popular as the notebook:
Help and Documentation
Help for sage is available from: http://www.sagemath.org/help.html
A beginner would probably start with the Tutorial at http://www.sagemath.org/doc/tutorial/index.html
Further Reading
At the web page http://www.sagemath.org/help.html you would, by and by, want to look at the Installation Guide and the Reference Manual besides a whole host of documentation at http://www.sagemath.org/doc .
Comments
Hao Wen: 20091201
While Sage is truly a powerful software, it still lacks some key features as of today (Dec. 1, 2009). Good news it is under development.
Plotting doesn't have a good label function. Axis can not be fine tuned as Matlab.
Pablo Angulo: 20100615
Hao, that's perfectly possible, and it's been so for a long time. Sage uses matplotlib for most graphics and you can even add labels in latex. Feel free to email sagesupport for these kind of questions.
Christian: 2011104
On Lucid I had to add the libgfortran library:
aptget install libgfortran3
..to get rid of this sage error: ImportError: libgfortran.so.3: cannot open shared object file: No such file or directory.